Personnel from the Massachusetts Institute of Technology, Harvard University, the Massachusetts General Hospital, and the Massachusetts Eye and Ear Infirmary have formed a consortium to investigate the auditory system. The studies proposed are oriented towards understanding the physiological mechanisms underlying human hearing although the experiments may be conducted on lizards and cats as well as humans. Teams of researchers are organized according to the expertise required to work on different levels of the system. The principal groups study (1) middle and inner ear mechanics, (2) transduction processes in the cochlea, (3) auditory-nerve activity, and (4) signal processing in the central nervous system. Clinical studies are based on applying the techniques and findings from the basic investigations towards the improvement of diagnostic and surgical procedures for hearing disorders.